ABCDEABCDE 90 91 92 93 94 95 96 97 98 99 Time at risk x x 6.0 10.0 8.5 5.0 Total years at risk 35.5 -- time followed x disease onset Person-time
{"Image DocumentName": "Person-time x x A B C D E Total years at risk 35.5", "Image ImageDescription": "Time at risk. A. B. C. D. E x. x. Assume a population of 5 persons. Person A is followed from 1990 until 1996 \u2026 because he may die or be lost to follow up\u2026 he will contribute 6 years to our observation. Person B is born in 1992 and develops disease in He or she will contribute 6 years to our observation. Person C contributes to the entire observation period of 10 years. Person D moves to the study area in 1991 and leaves the area in mid He will contribute for 8,5 yrs. Person E develops disease after 5 yrs. So our denominator will be the sum of the time of each individualat risk when they are free of disease which in our example are 35.5 years. Total years at risk time followed. x disease onset.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}